Collision induced dissociation of highly excited NO2 was observed for the first time for well characterized MgO(100) surfaces with parent and product angular resolution at various internal and incident translational energies, and with product NO state-selected detection. A model was developed which explains the results, and enabled comparisons with the corresponding gas-phase experiments. Scattering of HCl(v=0) was examined at incident energies 0.11-0.90 eV, and demonstrated the transition between direct-inelastic scattering to trapping-desorption. At low incident energies rotational and translational temperatures of scattered HCl were equal to the surface temperature, and residence times in the millisecond regime were observed at low surface temperature. When HCl(v=2, J=1) was scattered from the surface, vibrational excitation survived the process of trapping-desorption, and HCl in v=2 was scattered into the gas phase. The residence time, however, was less than a microsecond at all temperatures. These results were reconciled with the scattering results of HCl in v=0 using a model that described the competition between hopping on terrace sites, desorption, and deactivation on defect sites.

The interactions of vibrationally excited HCI(v =2) with MgO(100) surfaces have been examined in detail, with scattered HCI(v =2) detected state selectively by resonance enhanced multiphoton ionization (REMPI). Simulations using a random walk model and 'best estimates' for activation energies for desorption and hopping suggest that deactivation probably occurs at steps. In parallel, a new apparatus has been designed and built for a next generation of studies of molecular interactions on insulating oxide surfaces. Specifically, FTIR will be used to determine geometries and adsorption, and TPD, REMPI and other laser-based spectroscopies will be used to interrogate interactions of molecules and radicals with the surface and with other adsorbates.

Publisher Description

The only book to give a complete picture of current hydrogel research, covering all the major applications as well as the fundamental principles behind them.

In this book the author presents an up-to-date summary of existing information on the structure, electronic properties, chemistry and catalytic properties of transition metal oxides.The subjects covered in the book can be divided into three sections. The first (chapters 1 to 3) covers the structural, physical, magnetic, and electronic properties of transition metal oxides. Although the emphasis is on surface properties, relevant bulk properties are also discussed. The second section (chapters 4 to 7) covers surface chemical properties. It includes topics that describe the importance of surface coordinative unsaturation in adsorption, the formation of surface acidity and the role of acidity in determining surface chemical properties, the nature and reactivities of adsorbed oxygen, and the surface chemistry in the reduction of oxides. The third section (chapters 8 to 14) is on the catalytic properties. Various catalytic reactions including decomposition, hydrogenation, isomerization, metathesis, selective oxidation, and reactions involving carbon oxides are discussed. Emphasis is placed more on reaction mechanisms and the role of catalysts than on kinetics and processes. Chapters on the preparation of oxide catalysts and on photo-assisted processes are also included. Whenever appropriate, relationships between various topics are indicated.Written for surface physicists, chemists, and catalytic engineers, the book will serve as a useful source of information for investigators and as a comprehensive overview of the subject for graduate students.

This book provides final year undergraduate students, graduate students, research scientists and engineers with an up-to-date overview of the power of using surface analytical techniques for probing complex solid surfaces and lubricants as well as for understanding their interactions in tribological systems. The first three introductory chapters illustrate the need for surface analysis in tribology and the essentials of the analytical techniques. Following these, eight chapters on applications give insight into the contribution of the major analytical techniques to tribology. These chapters are divided into three groups. The first group deals with the applications of surface analytical techniques to the study of the adhesion, friction, deformation, wear, structure and chemistry of solid surfaces at the atomic scale or in well-defined conditions. The second group focuses mainly on solid lubricants and tribological surface modifications. Lastly, the third group covers liquid lubricants in molecularly thin-film lubrication and in boundary lubrication and their interactions with surfaces.

The book is a multi-author survey (in 15 chapters) of the current state of knowledge and recent developments in our understanding of oxide surfaces. The author list includes most of the acknowledged world experts in this field. The material covered includes fundamental theory and experimental studies of the geometrical, vibrational and electronic structure of such surfaces, but with a special emphasis on the chemical properties and associated reactivity. The main focus is on metal oxides but coverage extends from 'simple' rocksalt materials such as MgO through to complex transition metal oxides with different valencies.